1. Field of the Invention
The present invention relates to a heat sink module and a lighting device, and relates more particularly to a type of heat sink fin and a light emitting diode lighting device using the same.
2. Description of the Related Art
Light emitting diodes (hereinafter “LED”) were initially used only in indicator lights of electronic devices, and now are increasingly applied to the backlights of liquid crystal display devices, and even further to electrical illumination devices or public displays such as vehicle lighting apparatuses, traffic lights, electronic sign boards, large video walls or the illumination devices in projectors. Their range of applications continues to expand.
While light emitting diodes are emitting light, heat is generated, and LEDs producing higher luminous intensities generate greater levels of heat. If generated heat is not efficiently dissipated, the accumulated heat may quickly increase the temperature of the light emitting diodes and its surrounding environment. High temperature may have detrimental effects on the light emitting diodes. Therefore, in an LED light device, a heat sink is normally required to effectively dissipate the heat generated by light emitting diodes.
To date, the heat sink fins of many heat sink modules are produced using an aluminum extrusion process. FIG. 1 shows a traditional aluminum extrusion-processed heat sink module that is popular in the market. The heat sink module 1 includes a base 11 and a plurality of heat sink fins 12, which is directly formed on the base 11. The heat sink module 1 is fabricated by extruding aluminum or aluminum alloy through a die in an extrusion machine after the aluminum or the aluminum alloy is heated to a molding temperature (400° C.-500° C.).
Because aluminum or aluminum alloy is extruded through a die to form heat sink fins 12, the heat sink fins 12 of the heat sink module 1 have to be of at least a minimum thickness to avoid breakage during the extrusion process. If larger heat sink fins are desired, a new extrusion die must be prepared, and the manufacturing cost is increased. In addition, the required thickness of the heat sink fins limits the heat dissipation area of the heat sink module.
Consequently, if the heat sink fins 12 must be of at least a minimum thickness, the material cost is increased and the heat dissipation area of the heat sink module is limited.
As an alternative to the aluminum extrusion process, many heat sink modules are manufactured using die-casting method. The die-casting method is used to form a metal object by injecting molten metal into a mold cavity under a predetermined pressure. Compared to the aluminum extrusion process, the die-casting method can manufacture heat sink fins of more shapes and configurations. FIG. 2 shows another traditional heat sink module 1′, which includes a base 11′ and a plurality of heat sink fins 12′. The heat sink fins 12′ disposed in a radial manner on the base 11′ are produced using die-casting method.
Because the heat sink fins 12′ of the heat sink module 1′ are die cast, the heat sink fins 12′ have to be of at least a minimum thickness to avoid breakage when the heat sink fins 12′ are demolded. In addition, if heat sink modules 1′ with more or fewer heat sink fins 12′ is to be produced, a new molding die must be prepared, and the manufacturing cost is increased.
Thus, a method to make the heat sink fins of a heat sink module as thin as possible to lower their manufacturing cost is worth consideration by persons skilled in the art.